The present invention relates to the provision of environmental protection around wires, optical fibres or other elongate substrates.
It is often necessary to seal wires at their points of entry into housings in order to protect connectors or electronic components within the housing from moisture or other contaminants that might otherwise enter the housing through the opening provided for the wire. This problem frequently occurs in telecommunications networks where devices for connection, electrical protection or isolation, are positioned outside buildings and are expected to have a long life-time under unfavourable weather conditions.
The invention is therefore particularly concerned with a device comprising some form of housing which has means for sealing wires at or adjacent their points of entry.
U.S. Pat. No. 4,859,809 (Jervis) discloses a splice case for sealing connectors joining small pair count telecommunications cables. First and second half-shells contain a gel sealing material and are held together by springs that function also to deform surfaces of the half-shells to put the sealing material therein under compression. The conductors enter the half-shells at their ends and lie between two layers of gel.
A two part closure for sealing wire connectors is also disclosed in U.S. Pat. No. 4,849,580 (Reuter). Again, each part contains a sealing material.
Reference may also be made to U.S. Pat. No. 4,963,700 (Olsen), U.S. Pat. No. 3,879,575 (Dobbin et al), U.S. Pat. No. 4,610,738 (Jervis), U.S. Pat. No. 3,757,031 (Izraeli) and DE G9004669.2 (3M). These documents confirm the common practice of providing sealing material in each of two half-shells that are brought together around the conductor to be sealed.
We have discovered that, particularly with careful choice of sealing material, a more economical sealing device can be produced.
Surprising, a single layer of sealing material can be caused to fold, or wrap, around a conductor to be sealed by lateral displacement of the conductor into the sealing material. This preferably occurs as parts of a sealing device are closed around the conductor.